【Objective】The purpose of this study is to assess the growth characteristics and adaptability of (Betula platyphylla×B. pendula) half-sib families through regional trials conducted at different test sites, thereby providing scientific guidance for the selection and application of superior families as well as the reconstruction of seed orchards. Specifically, the study aims to clarify the genetic variation patterns of key growth traits among families and across environments, and to identify families with excellent growth performance and wide adaptability.【Method】The research materials are from 10-year-old tetraploid and diploid (B. platyphylla×B. pendula) half-sib family test forests located in Dandong, Shangzhi and Qing’an test sites. Traits including tree height, diameter at breast height (DBH), stem straightness, and survival rate were systematically investigated in each family. A heteroscedastic mixed linear model was applied to analyze the fixed effects (e.g., site effects) and random effects (e.g., family effects, block effects, and family×site interaction effects) of each trait across multiple sites. The combined best linear unbiased prediction-genotype main effect plus genotype×environment interaction (BLUP-GGE) analysis method was used to estimate the comprehensive breeding values of each family, while GGE biplot analysis was employed to evaluate the adaptability and stability of families across different test sites.【Result】(1) The site effects on tree height, DBH, individual tree volume, and stem straightness of (B. platyphylla×B. pendula) half-sib families were extremely significant (P<0.01). Except for stem straightness, the differences in other traits among families and blocks, as well as the family×site interaction effects, all reached significant levels (the ratio of variance component to standard error (z._ratio) ≥1.5), indicating obvious genetic differentiation and environmental adaptation differences among families. (2) Analysis of variance for each test site revealed that, except for the survival rate at Qing’an test site, the differences in all other traits among families were extremely significant (P<0.01). Among all traits at Dandong, Shangzhi, and Qing’an test sites, the individual tree volume exhibited the largest coefficient of variation, which was 72.37%, 56.37% and 49.86%, respectively, indicating the highest genetic variation and selection potential. (3) GGE biplot analysis indicated that the three test sites could be divided into three distinct suitable growth regions due to differences in environmental conditions. The families that performed best at Dandong, Qing’an, and Shangzhi test sites were family 205, 305 and 325, respectively. Compared with the average value of diploid families, their individual tree volume growth increased by 18.51%, 2.60% and 20.57%, respectively. Based on a 20% selection rate and comprehensive evaluation across the three test sites, families such as 325 and 316 were selected as superior families with fast growth and high stability, with the genetic gains of individual tree volume reaching 5.50% and 12.92%, respectively.【Conclusion】There were significant differences in various traits of (B. platyphylla×B. pendula) families between test sites and among families, indicating the strong genetic control and environmental sensitivity of these traits. Based on the BLUP-GGE biplot analysis of growth traits, the three test sites were classified into different suitable growth regions. Families 325 and 316 were identified as superior families with fast growth and high stability, which could provide valuable genetic resources for the genetic improvement and sustainable management of (B. platyphylla×B. pendula) plantations.