Abstract: This paper discussed the decisive factors affecting the ability of earthquake early warning. Based on the distribution of existing seismic networks， data transmission delay and network running state， we analyzed whether they meet the needs for earthquake early warning， and made corresponding recommendations in order to improve the situation. Results show that the status quo of China earthquake networks did not meet the needs for earthquake early warning. Therefore, besides raising the network density and its operation rate, we should upgrade the existing seismic data acquisition system and real-time transmission software so as to satisfy the data transmission demand for earthquake early warning.