We build a partition function model by product approximation first,then put the normal temperature calculated by moment square R2v,which has no rotational transition,approximately as a constant and applied to high temperature,and lastly program the compiler and compute the spectral line intensities and absorption coefficients of the 001-000 band for the hydride BH2 free radical molecule at several temperatures.The results show that the calculated values of total partition function agree with the data obtained from Gauss calculations and the fitted values by five factorial polynomials.Such excellent agreement has made it feasible to calculate the spectral line intensities and absorption coefficients at different temperatures.From the spectral figures at different temperatures,we find that they accord with the spectrum characteristic of asymmetric top molecules in some literature.This analysis has significance in measuring the high-temperature spectrum intensities of radical molecules by experiment.