Abstract: Abstract: 【Objective】The Pinus koraiensis Sieb. et Zucc(Korean pine)and Larix olgensis Henry(Olgan larch)are the main afforesting tree species in Heilongjiang Province. Developing outer crown profile models for the two tree species will provide references for forest management of plantations. 【Methods】The branches from 50 trees of planted Korean pine and Olgan larches were used. The segmented polynomial equation, modified Kozak equation, and modified Weibull equation were used as the basic model, and a nonlinear mixed-effects model at the tree level was developed. The crown profiles of the two tree species were compared. 【Results】For both tree species, the segmented polynomial predicted model, included diameter at breast height(DBH), crown length(CL), crown ratio(CR), and height to diameter ratio(HD), the modified Kozak predicted model included DBH, CR and HD, and the modified Weibull predicted model included DBH, CR and HD. By including mixed-effects into the models, the goodness of fit for all the models was improved compared with the basic models. The modified Weibull equation performed best for both Korean pine and Olgan larch. However, there was not a large difference between the modified Kozak equation, Weibull equation, and the segmented polynomial equation. As for the Korean pine, the crown radius of the lower crown estimated by the segmented polynomial predicted model was lower than that of the modified Kozak and Weibull equation, whereas the differences between the three models for the Olgan larch were relatively less. 【Conclusion】 The segmented polynomial equation, modified Kozak, and modified Weibull equation performed well in crown profile modeling with high accuracy. Fewer variables were included in the modified Kozak equation and modified Weibull equation than the segmented polynomial equation. The parameter estimation for the modified Kozak and Weibull equation were also stable, and the crown volume and surface area were easy to calculate by integration.