The Microtops Ⅱ is a handheld multiband sunphotometer capable of measuring the aerosol optical depth (AOD). Some experiences and tips for use are given. The principles of application, major features, the calculation of AOD and the calibration method of the instrument are introduced. An analysis is made of a set of data the on contrasting observation at the National Nanling Forest Park on 19 September 2004. The results show that the AOD values differ by 0.01 at most at the 500 nm channel, and the calibration constants are suitable for the two instruments.