Abstract:By using litterbag method, the decomposition processes of 9 types of f oliar litter in secondary conifer and broadleaf mixed forest in Changbai Mountai ns were assessed during a period of 34 months. The initial N and P concentration s varied greatly among the litters, and there were significant relationships bet ween litter decomposition constant (k) and initial N concentration and C/N. The percent organic matter remaining had a significant linear correlation with perce nt C remaining, and a significant polynomial correlation with percent N and P re maining. The percent N and P remaining increased with the decomposition of organ ic matter in its initial decomposition phase, but decreased gradually in the lat ter decomposition phase. C/N and C/P declined with the decrease of percent organ ic matter remaining, and the differences in C/N or C/P among litter types decrea sed, being approached to 23 and 350, respectively by the end of the study. Durin g organic matter decomposition, N/P did not change greatly, and the differences in N/P between litter types declined when the percent organic matter remaining w as below 25%. Our study showed that percent of C、N and P mass remaining can be predicted by percent of organic matter mass remaining.