Abstract: Reservoirs in member H3 of Yanglou Oilfield is at the early diagenetic stage B subage period, the diagenesis of which can be divided into mechanical compaction, cementation and denudation. The period of diagenesis is also the evolution process of reservoir porosity. According to the method on reservoir restoration and evolution calculation of Beard, reservoir evolution pattern has been established and quantitative calculation of reservoir restoration from oil group Ⅳ to Ⅵ of member H3 has been carried out. The calculation result approximates to the value of core analysis, which indicates the predictive value of reservoir evolution is basically credible. Therefore, the evolution calculation of porosity has great directive value toward reservoir evaluation in Yanglou Oilfield.