The invention provides a bolometer and a manufacturing method thereof. The resistance value of thermistors of the bolometer can accord with design specification by changing the structures and the doping density of the thermistors so as to meet the application requirement. The structure thereof comprises a base, a support layer positioned above the base, a lower electrode manufactured on the support layer, thermistors manufactured on the lower electrode, an upper electrode covering the thermistors and an absorbing layer manufactured on the upper electrode, wherein the base and the support layer are parallel to each other and are arranged at intervals, and the upper electrode, the lower electrode and the thermistors are electrically connected in parallel. The thermistors are arranged at intervals between the upper electrode and the lower electrode. The structural arrangement enables the resistance value of the thermistors to be adjustable in a large range, optimizes the performances of devices and meets different application requirements, thereby greatly improving the flexibility of design.