A method of reporting UE measurement state information in RLF report is provided. A UE performs radio measurements of a serving cell and neighbor cells in a mobile communication network. The UE evaluates a measurement reporting criteria and attempts to access the network to deliver a measurement report if the criteria is met. The UE then detects a radio link failure or a handover failure event and reconnects to the network by performing RRC reestablishment or RRC establishment. Finally, the UE transmits a failure event report to the network. The failure event report comprises UE measurement state information corresponds to the failure event. The UE measurement state information helps the network to determine whether to apply corrective actions to mitigate the failure.