The Unmanned Aerial Vehicle (UAV) has been widely applied to various applications, such as the enemy investigation in war, image transmission of military usage by satellite, and the transmission of control signal and image through radio frequency. The civilian UAV typically uses satellite, Global Positioning System (GPS), Wi-Fi or the third generation of mobile phone mobile communications technology (3G) for communications. However, the transmission range limits the data transmission of civilian UAV. In this paper, we utilize the 3G communications and consider the signal quality of Base Stations (BSs) for path planning. We adopt the well-known A Star search algorithm to prevent the dead end of signal during flight, and plan the better flight path for civil UAV. The simulation results show that our proposed method acquires the 2.44 times better communication quality and routes with the 1.56 times longer flight only.