Abstract: On the basis of imbibition model, taking development experiences home and aboard and core experiments into consideration, this paper analyzes various fluid forces in fracture matrix reservoirs and studies the imbibition characteristics of low permeable fracture then gets a new way to determine relevant parameters such as absorbing pressure, injection pressure, water injection rate and water injection cycle. All these provide the theoretical foundation for the promotion and application of imbibition oil recover-y in low permeable fracture reservoirs.