In this study, to achieve high-speed, high-sensitivity, and low-cost laser communication, we optimized and improved a new InGaAs/InP single-photon avalanche diode (SPAD) to better apply to the near-infrared laser communication system detected using a single single-photon detector (SPD). Compared with the previous generation, we added a dielectric-metal reflective layer and improved the double Zn diffusion process while optimizing the structure of each layer. The fabricated InGaAs/InP SPAD achieved a photon detection efficiency (PDE) of 30%, a dark count rate (DCR) of 3 kHz, and an afterpulsing probability (P_ap) of 2.4% under a high-frequency sine-wave gate (SWG) operating mode with a frequency of 1.25 GHz, temperature of 225 K, and bias of 6 V. A free-running negative feedback avalanche diode (NFAD) prepared based on the high-performance SPAD was used as a receiver in the real-time spatial laser communication system. The performance parameters of the laser communication system with the NFAD were experimentally obtained. The experimental results show that the InGaAs/InP NFAD with a bit rate of 1 Mbit/s using the 4-pulse position modulation (4PPM) scheme has a bit error rate of 1.1×10^-5 and sensitivity of -69.6 dBm.