Abstract: A method was introduced to classify two-dimensional particle images collected using optical array probes. Cloud particles were grouped into eight types on the basis of particle morphological parameters, including tiny, linear, aggregate, graupel, sphere, hexagonal, irregular, and dendrite. Mass and habit were assigned to each particle according to liquid water and ice water contents. This method was used to analyze cloud microphysical data obtained by an aircraft on April 6, 2006, in Beijing. The occurrence frequency of the aggregate, graupel, and hexagonal, was 78%. The fraction of graupel increased with an increase in particle size at four temperature intervals between -20℃ and 0℃. The liquid water content, liquid particle concentration, and ice particle concentration of the nonprecipitating clouds were considerably smaller than the same values of precipitating clouds. In the detected nonprecipitating clouds, the mean values of the liquid water content, ice water content, and ice particle concentration were 0.01 gm^-3, 0.007 gm^-3 and 11.9 L^-1, respectively.