We theoretically study the quantum Fisher information (QFI) of the SU(1,1) interferometer with phase shifts in two arms by coherent （×） squeezed vacuum state input,and give the comparison with the result of phase shift only in one arm.Different from the traditional Mach-Zehnder interferometer,the QFI of single-arm case for an SU(1,1) interferometer can be slightly higher or lower than that of two-arm case,which depends on the intensities of the two arms of the interferometer.For coherent （×） squeezed vacuum state input with a fixed mean photon number,the optimal sensitivity is achieved with a squeezed vacuum input in one mode and the vacuum input in the other.