The location and the temperature of event horizon of Kerr- Newman space-time can be easily determined by supposing that line element represented with Tortoise coordinate is conformal to 2-dimensional Minkowski space-time near the event horizon.

• 如果令乌龟坐标下的二维时空线元在视界附近共形于明氏时空；可以容易地定出Nerr-Newman黑洞视界的位置和温度.