Based on the rate equations describing the semiconductor lasers with optical feedback and optical injection, the influences of the feedback strength and delay time, injection strength and frequency detuning on the self-correlation performance of the output chaotic signal have been investigated. The results show that the full-width at half-maximum (FWHM) and peak sidelobe level of the output self-correlation function is critically dependent on parameters related to injection and feedback. Through reasonably selecting the parameters, the self-correlation function with 0.02ns FWHM can be obtained, which is superior to the reported results.