The characteristics of crown structure, root systems and biomass productivity of a coconut-pineapple interplantation are investigated. The results obtained show that the leaves of coconuts distributed mainly in the 2 -9m from aboveground, but pineapple’s leaves distributed mainly in from 0 to 80 cm; The roots of coconuts concentrated in deeper soils, but the roots of pineapples mainly concentrated in 0-30 cm surface soils. The vertical distribution of leaves and roots in the coconut-pineapple interplantation are appropriate for full utilization of light energy and soil nutrients. Biomass productivity of the interplantation is 4. 3 times that of pure coconut stands. Thus, coconut interplanted with pineapple is one of the optimum cultural patterns in tropical areas.