Internet of Vehicle (IoV) is playing an increasing important role in constructing Intelligent Transport System (ITS) of safety, efficiency and green. Safety applications such as Emergency Warning and Collision Avoidance require high reliability and timeliness for data transmission. In order to address the problems of slow response and local broadcast storm existing among waiting-based relay strategy of emergency message, a Local topology Information Sensing technology based broadcast (LISCast) protocol is proposed in this paper, making use of the advantage of probability-based forwarding scheme in redundancy inhibition. According to the beacons broadcasted periodically between vehicles, LISCast collects neighbor's number and distribution, from which the characteristic information such as effective candidate number and maximum distance are extracted. Through embedding them into the header of broadcast packets, the alternative receivers uniformly schedule rebroadcasting priorities in a distributed and adaptive way at the cost of little overhead due to absence of roadside unit. The simulation results show that LISCast improves the ability to adapt to dynamic topology by optimizing the performance of delay and redundancy upon the condition of guarantee the transmission reliability.