In this pape r,we analyze and simulate the temperature effect on electro-optical behavior of single quantum well laser diodes (SQW-LD) both in time and frequency domains.M odeling of SQW-LD based on three-level rate equations by means of Matlab Simul ink is given and various simulations are present.The results show that the SQW- LD has good temperature property and wide modulation bandwidth.When the temperat ure increases from 250 K to 350 K,the modulation bandwidth decreases only from 2 5.00 GHz to 21.72 GHz.