Abstract: In order to clarify the effects of forest gap size on the growth and stem form quality of Taxus wallichina var. mairei and effectiveness of the precious timbers cultivation, 25 sample plots in Cunninghamia lanceolata forest gaps were established in Mingxi County, Fujian Province, China to determine the indices of the growth, stem form and branching indices of T. wallichina var. mairei seedlings. The relationships between the gap size and growth, stem form and branching were investigated. The 25 sample plots were located at five microhabitats which were classified based on gap size as follows: ClassⅠ, Ⅱ, Ⅲ, Ⅳ and Ⅴ, which had a gap size of 25-50 m², 50-75 m², 75-100 m², 100-125 m² and 125-150 m², respectively. The evaluation index system of precious timbers was built by using hierarchical analysis. The 5 classes of forest gaps were evaluated comprehensively by using the multiobjective decision making method. The results showed that gap size significantly affected 11 indices, i.e., height, DBH, crown width, forking rate, stem straightness, stem fullness, taperingness, diameter height ratio, height under living branch, interval between branches, and max-branch base diameter. ClassⅠand Ⅱ both significantly promoted the growth of height, DBH and crown width, and both significantly inhibited forking rate and taperingness, and improved stem straightness. ClassⅡ significantly improved stem fullness and diameter height ratio. ClassⅠand Ⅱ significantly improved height under living branch and reduced max-branch base diameter. Class Ⅰ significantly increased interval between branches. ClassⅠandⅡ significantly improved the comprehensive evaluation score of precious timbers. This study suggested that controlled cutting intensity could be used to create forest gaps of 25-75 m², which improved the precious timber cultivating process of T. wallichina var. mairei in C. lanceolata forests.