The invention discloses a method and device for planning smooth paths of a mobile sink. The method includes the steps that a certain number of nodes are deployed in a monitoring region, and multiple nodes to which the mobile sink needs to have access are determined; current coordinates of the mobile sink and coordinates of multiple sensor nodes to which the mobile sink sequentially has access are acquired; a first angular bisector among the current mobile sink, the first sensor node and the second sensor node is acquired in real time; a reference point of the first angular bisector is acquired, and the first smooth arc path of the mobile sink within the sensing range of the first sensor node is acquired according to the reference point; in this way, the (N-1)th angular bisector among the current mobile sink, the (N-1)th sensor node and the Nth sensor node is acquired sequentially in real time, wherein N is larger than 2; the (N-1)th smooth arc path of the mobile sink within the sensing range of the (N-1)th sensor node is acquired according to a reference point of the (N-1)th angular bisector. The method can rapidly collect data in a network, and energy is saved.