The diffraction characteristics of transversely chirped volume Bragg grating are analyzed using beam propagation method. The power, spectral and wavelength tuning characteristics of external cavity diode laser analyzed by laser using transversely chirped volume Bragg grating are demonstrated. The theoretical and experimental results indicate that the peak diffraction efficiency of transversely chirped volume Bragg grating decreases with increasing the size of the incident beam in chirped direction, the spectral width increases with increasing the size of the incident beam in chirped direction. When the chirped direction of the transversely chirped volume Bragg grating is consistent with the fast axis direction of diode laser, external cavity efficiency of external cavity diode laser is 85% , the spectral width of the output laser at 808.05 nm is 0.27 nm. When the chirped direction of the transversely chirped volume Bragg grating is consistent with the slow axis direction of diode laser, external cavity efficiency of external cavity diode laser is 89% , the spectral width of the output laser at 808.05 nm is 0.3 nm. Both of the external cavity diode lasers have a better way to achieve about 15 nm wavelength tunable range, and within the entire tuning range, the fluctuation range of output power are less than 1% (consistent with the fast axis direction) and 1.5% (consistent with the slow axis direction) respectively.