Disclosed are a root canal fluid filling device and method. The root canal fluid filling device includes a root canal filling device box, including an upper box body and a lower box body which are arranged in upper and lower partitions and detachable; a positive and negative pressure generating apparatus, arranged in the lower box body; an air pressure monitoring apparatus, arranged in the lower box body and connected to the positive and negative pressure generating apparatus; an air pressure recovery apparatus, arranged in the lower box body; an auxiliary positioning apparatus, including an auxiliary positioning crown which is respectively connected to the positive and negative pressure generating apparatus, the air pressure monitoring apparatus and the air pressure recovery apparatus and is to be sleeved outside and cemented to a tooth to be subjected to root canal therapy; a control display apparatus; and a power supply apparatus.