In the process of urban expansion in the central Guizhou, a large number of isolated island like natural mountains were embedded into the built-up area. These urban remnant mountains that retain the original habitat can be considered as urban remnant mountain wilderness (URMWs) in a completely artificial urban environment. Due to the different degrees of human interference, the wild degree of URMWs are different. Accurate evaluation of the wild level of URMWs could provide scientific basis for the protection of URMWs. In this study, the typical multi-mountainous city in southwestern karst region of China was selected as the research area. Among the urban remnant mountains with good original vegetation and relatively complete shape, 18 URMWs were randomly selected as the research objects. The analytic hierarchy process, entropy weight method and comprehensive weight method were used to construct the evaluation indicator system of natural wildness of URMWs in karst region. Through the field investigation combined with remote sensing technology, the indicator data of sample URMWs were obtained, and the natural wildness evaluation value of each sample URMW was obtained by weighted linear combination. Finally, the natural wildness threshold of URMWs was determined and graded by normal distribution method and expert diagnosis method. The results showed that:(1) the natural wildness indicator system of URMWs were composed of three criterion layers (i.e. mountain characteristics, animal and plant characteristics, environmental characteristics), seven indicator layers and 26 evaluation factors. The indicator system could be suitable for evaluating the natural wildness of URMWs in karst areas. (2) The average value of mountainous characteristics, animal and plant characteristics, and environment characteristics of URMWs were 0.56±0.13, 0.44±0.07, and 0.48±0.12, respectively. (3) The natural wildness of URMWs were separated into four ranks:high wildness, medium wildness, low wildness and no wildness. The threshold of natural wildness of URMWs was 0.43, the URMWs area with natural wildness accounted for 75.6% of the total area of the selected sample URMWs. The research results would provide a basic theory for judging the natural wildness of URMWs in the artificial environment of multi-mountainous cities, and provide a scientific basis for formulating urban wilderness protection strategies.