Through the experiment of selective infrared radiation and vacuum drying and drying quality for litchi, it is found that the spectrum matching of litchi's flesh for radiation source has significant effect on drying rate, and the matching between vacuum and radiation heat flux has effect on drying rate and drying quality. The results show the optimum drying conditions are radiation source SZ, radiation distance 120mm, heating and tempering time 15min/15min and vacuum degree 0.02MPa respectively.