Coverage problem is a fundamental issue in wireless sensor networks. In this paper, we consider two sub-problems: κ-coverage rate evaluation and κ-coverage rate deployment. The former aims to evaluate the ratio of κ-covered area relative to the monitored area, while the latter aims to determine the minimum number of sensors required and their locations to guarantee that κ-coverage rate of the monitored area meets application requirements. For κ-coverage rate evaluation problem, a non-uniform-grid- based approach for random deployments is proposed. For κ-coverage rate deployment problem, a greedy-based approach is suggested to meet the requirement of κ-coverage rate. Simulation results show that both our schemes are more time efficient than previous work.