Studies for stand-alone microgrid optimization exist the problems of simple micro-source type, few design scenarios and neglect to controllable load. This paper presents a multi-objective optimization model including power generation cost, load cut compensatory and environmental benefit under the condition where controllable load is treated as power balancing means. Four typical scenarios are designed according to the working day, weekend and sunny, cloudy and rainy days. With the difficulty of multi-variables and complex scenarios, a modified CPSO algorithm is proposed to realize economic dispatch of stand-alone microgrid under the constraints such as power balance. The results in numerical example verify the validity of the presented model and algorithm to multi-scenario microgrid optimization problem. This work is supported by the Major Key Science and Technology Project in Renewable Energy Area of Yunnan Province (No. 2013ZB005), the Science and Technology Project of Yunnan Power Grid Co., Ltd (No. YNKJQQ00000280), and the State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources (No. LAPS16007 and No. LAPS16015).