Chrome browser provides a RRTCC (receiver-side real-time congestion control) algorithem for WebRTC, but it exhibits poor performance in the mobile network environment. It cannot effectively compete with other TCP flow applications, causing WebRTC starvation. Furthermore, in the case of multi-WebRTC concurrent flow, new entrants will impact the existing flows. This paper proposes a transmission control strategy MTCIS. The core of MTCIS is the use of an improved RRTCC algorithm in consideration of mobile network scenarios and QoE, and the proper control of WebRTC, which can avoid the problem of excessive concession when competing with TCP flow. While in multi-WebRTC flow concurrent scenarios, the MTCIS can dynamically adjust the transmission parameters of video streaming, based on the analysis of rational utilize bandwidth and priority to satisfy users' QoE. Experimental results show that MTCIS can be used in mobile network environment of flows competition, ensure reasonable competition, stability and robustness of WebRTC, which improves the users' QoE.