For instantly monitoring the safety status of lithium-ion batteries, this letter provides a scheme of insitu monitoring system of lithium-ion battery based on multifunctional fibers and constructs the corresponding test system. In this scheme the distributed temperature sensing system(DTS) is employed for testing the temperature of lithium-ion batteries and the distributed gas detection system combined with trace gas sensors based on TDLAS technique and optical switch control is utilized for monitoring the leakage of lithium-ion batteries. Aiming at the character of the large deformation of lithium-ion batteries especially in soft packed batteries, a wide-range deformation test scheme is designed. The preliminary test results of the in-situ monitor system of lithium-ion battery indicate that the temperature accuracy of this system is ±1 degrees centigrade and the spatial resolution is 1 meter. The resolution of gas detection of CH4, CO, CO2 and HF gas meets the design. The strain range of the system is 10000με and the accuracy is 100με . The system meets the demand of insitu monitoring of lithium-ion battery.