[Objectives]  To improve understanding of the economic benefit of the pollination of rape crops by the Mason bee Osmia excavata Alfken, an important pollinating insect. [Methods]  Rape fields were divided into two areas, an O. excavata pollination treatment area and an O. excavata exclusion area, before flowering. Cameras were used to record the process and effect of O. excavata pollination on rape plants. Based on the honey bee dependent market valuation method and China's national conditions, we evaluated the economic value of O. excavata pollination of rape in 2015, and explored its importance for rape production. [Results]  More than 60% of bees left their nests from 7 to 8 a.m. and returned between 4:30 and 5:30 p.m; an active period of about 9.58 h.The average duration of visits to each flower was 10.89 s.The pollination area had 2.74%, 4.81% and 11.48% higher seed weight,silique ratio and grain number, respectively, than the exclusion area. Based on the 2015 data, the amount of rape seed attributed to pollination by O. excavata in China is estimated to exceed 3.733 million tons with a total pollination service value of more than 194.102´10⁸ yuan. [Conclusion]  Pollination of rape by O. excavata has important economic benefits and it is therefore important to find ways to protect O. excavata populations and enhance the pollination activity of this species during the rape flowering period. Public awareness of the economic benefit provided by O. excavata should be improved.