Humidity measurement plays an important role in various industries for the reliable operation systems and optimization of processes. Therefore monitoring and controlling the humidity is of great concern. MEMS humidity sensor has the advantages of light weight, small size, low cost, and ease of integration.. In MEMS, a simple micro-cantilever beam has been found to be highly suited for sensing purposes. The objective of this paper is to present the design of micro-cantilever humidity sensor, based on principle of capacitance and various analyses performed on the device. The cantilever beam and the underlying electrode are made of platinum and these structures act as parallel plates of capacitance. The structure is designed and simulated using CoventorWare 2010 and the results are verified with those of the mathematical model using Matlab. This structure exhibits good linearity in human adaptive ranges. Absorption of moisture by cantilever beam increases the mass which in turn deforms the beam leading to significant change in capacitance.