Abstract: This paper a ims at studying the grow th characteristics ofP inus ponderosa on the basis of the field investiga tion data, andmeasuring through experim ent the related index of its cold resistance w hose mechan ism w as analyzed and eva luated. The research w ere as follosw: P. pond erosa had a strong root system; its vertical roots had astrong grow ing ab ility; the seed lings had a h igher surv ival rate; and the diameter grow th o f 1-year-o ld P. ponderosaseedlings was obv iously faster than that ofP. tabulaeformis. Wh ile the grow ing processes of the seedlings of the tw ospeciesw ere sim ilar to each o ther, seven years after its plant ingP. ponderosa began to enter its fast g row ing period,w ith an average annual he ight grow th of 45 cm, and kept increasing. The annua l and to tal d iam eter grow th of P.p onderosa w as obviously faster than that ofP. tabu laeform is, but the heigh t o f the form er w as low er than that of thelatter. The vo lume o f 18-year-o ld P inus ponderosa w as 0. 017 7m3, 10% larger than that ofP. tabulaeform is. Thediameter grow th o f young p lants o fP. p onderosa obv iously varied in different areas, rang ing from 0. 30 to 0. 94 cmyearly. Theme teoro log ica l factors had certa in effects on its grow th, and the inerement increased apparentlyw ith theincreasing of active accumulated tempera ture and sunsh ine-hours. The he ightw as obv iously re lated to the d iameter of the trees, the length o f new ly-grown branches, and its crow n, and the correspond ing coefficient betw een the heightand its diameter increased w ith the grow ing of its age. Themeasurement of co ld resistance show ed that the exudationrate of electro lyte o fP. ponderosa w as higher than that o fP. tabulaeform is at every low-tempera ture phase. The LT50w as - 10. 7℃, w hile that o fP. tabulaeform isw as - 17. 9 ℃. The re lative low content of bound w ater, soluble sugar, K+, Caroteno id and ABA in the leaf tissue ofP. p onderosa w as the interna l cause of its w eak co ld resistance.