To investigate the effects of different artificial woodlands on soil microbial biomass and microbial functional diversity, a case study was done on three artificial woodlands (Robinia pseudoacacia, Hippophae reamnoides, and Prunus armeniaca) in the hilly area of the Loess Plateau, located at the Yangjuangou catchment, Yanan city, Shannxi. Among the three artificial woodlands, we found soil microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) of Robinia pseudoacacia were both highest. The average well color development (AWCD), which represents soil microbial metabolic activity, followed a similar trend with MBC, in the order of Robinia pseudoacacia＞ Hippophae reamnoides＞Prunus armeniaca. AWCD was also significantly correlated with microbial biomass, total nitrogen, and soil moisture. The difference in microbial functional diversity among the three artificial woodlands was not significant; Shannon-Winner index was Robinia pseudoacacia＞Prunus armeniaca＞Hippophae reamnoides and did not have obvious correlations with microbial biomass or soil physiochemical characteristics. We draw the following conclusions: (1) among three artificial woodlands, Robinia pseudoacacia had the most microbial biomass and activity; (2) there were no significant effects of the different artificial woodlands on soil microbial diversity.