The LICOR-6262 analyzer was used as the mainbody in combination with a modified closed gas system,to explore effect of assumed balancing time and environmental temperature on results of the measurement.Results of the exploration showed ①balancing time of the closed gas system had significant effect on results of the measurement.With the time prolonged,the testing results decreased in value to a varying extent,②environmental temperature also influenced testing results significantly.Compared with the required environmental temperature,25℃,a low temperature (20℃) significantly affected the testing results (P<0.05),but a high temperature (30℃) did not (P>0.05).