China is part of the western Pacific region, which is the source of the most frequent tropical cyclones in the world. These cause severe disasters each year, including huge economic losses and casualties. To better understand their frequency and intensity, remote sensing tropical cyclone data were obtained for the entire Northwest Pacific region for the period 1977–2018. MATLAB and ArcGIS were used to analyse the frequency and intensity of tropical cyclones and their characteristics in various regions of China. At the same time, the influence factors of tropical cyclone characteristics such as El Niño and SST were analyzed by correlation analysis and Geographical detector. The annual frequency of tropical cyclones in the Northwest Pacific showed a fluctuating state, but the overall trend was decreasing. In particular, since 1994, the overall frequency decreased significantly but rebounded in recent years, while the intensity did not change significantly. It was found that cyclone intensity is lower when the frequency is higher, and vice versa. 85% of tropical cyclones occurred in summer and autumn, with the highest intensities in autumn, when the maximum average wind speed peaks at 37 m/s. The area with the most frequent tropical cyclones was 5–20° N, 125–155° E. A total of 314 tropical cyclones arrived in China during the study period, an average of about 7.5 per year. Their frequency and intensity gradually decreased as they moved from coastal to inland areas. Both SST and El Niño are significantly related to the formation and development of tropical cyclones, and the contribution of multiple factors interaction to the variation characteristics of tropical cyclones is significantly higher than that of single factors. Understanding the characteristics of the Pacific tropical cyclones is an important step in planning disaster prevention framework.