The vertical cavity surface emitting laser (VCSEL) based on graded distributed Bragg reflectors (DBR) consisted of a top mirror of 20 pairs of AlxGa1-xAs/AlyGa1-yAs (x=0~0.9, y=0~0.12) quarter-wave stacks and a bottom mirror of 34 pairs of AlyGa1-yAs/AlxGa1-xAs quarter-wave stacks has been demonstrated. Using two proposed transfer matrix methods, the simulation of DBR reflectivity depending on temperature refractive index of AlxGa1-xAs and AlyGa1-yAs are discussed and investigated. The simulation results could be achieved to well predicted the DBR performance under operating temperature variances, i.e., the temperature on varying reflectivity and full width half maximum (FWHM), wavelength stop-band shifts of the laser reflector, where using the multi-layer films evolution software of essential Macleod and modified transfer matrix method, respectively. Under our simulation, assuming the physically VCSEL device feature such as the linear grading DBR structure sandwiched with a n-type GaAs substrate and air films, we have systematically studied the temperature effects on the key parameters of top and bottom DBR schemes. In contrast with the temperature dependent DBR on the 850nm-VCSEL characteristics simulated with the above two transfer methods, the temperature varying spectra of VCSEL are agreed with the our simulated results presented in this paper. Also the temperature dependent model of DBR based on refractive index of graded multi-AlxGa1-xAs/ AlyGa1-yAs has been proposed. So, a series of optoelectronic measurements experimentally confirm our results again. The maximum reflectivity of the top and bottom DBRs are 96.4 and 99.98%, respectively. The central wavelengths of the bandwidth spectra in the top and bottom DBR are same. i.e., 840nm. These results can be obtained the criteria for the high performance VCSEL design. The far-field patterns of transverse electromagnetic fields confined in <15μm active-layer aperture of selectively oxidized VCSEL have been observed.