Growing urban population may cause severe resource as well as social impacts. So, managers at urban parks are often faced with the fundamental question of what level of visitor use can be accommodated in a park or recreation area so that natural and cultural resources and the quality of the visitor experience do not deteriorate to unacceptable levels. Within the outdoor recreation ?eld, this issue is referred to as carrying capacity and is often addressed through indicator-based planning/management frameworks such as Limits of Acceptable Change and Visitor Experience and Resource Protection. Such frameworks usually include 1) a set of elements that describe desired future conditions for natural/cultural resources and visitor experiences, 2) associated indicators of quality for park resources and visitor experiences, and 3) established standards that de?ne minimum acceptable conditions for indicator variables. The aim of this study was determination of critical indicators that were influenced visitor satisfaction in main urban parks of Karaj city and quantification standard level via visitor’s view. In this study, Limits of Acceptable Changes framework in four stages was used. By using questionnaire and literature review, data were collected. In the first stage, questionnaires were distributed among green space experts. The result of those questionnaires was used in the third stage questionnaires which were distributed among visitors of mentioned urban parks in summer. Finally, in the fourth stage, questionnaires were distributed among visitors in five urban parks. Data were analyzed by description and analysis statistics in SPSS software. Frequency distributions, Means, Median, and Mode were used for classification of recreational problems, selection of key indicators, and quantification of indicators standard level. Moreover, Kruskal- Wallis Test was applied in order to precision increase for selecting indicators and urban parks in the final stage of study. The validity of the questionnaires was approved through panel of expert’s judgment and the reliability of the main scale of the questionnaire was 0.8 for the parks problems variable. The results showed that in 5 main urban parks of Karaj, Bower, Buffet, Tap and Washstand as management indicators and Population as social indicator should be assessed. Based on the visitor’s view, these indicators have maximum and minimum standard level including 10 and 20 Bower, 2 and 4 Buffet, 10 and 20 meters to Tap, 20 and 30 meters to Washstand, 603 and 1120 people per hectare. These data help to managers to monitor critical indicators and their standards to maintain acceptable conditions of park for visitor’s optimum and continuous use. In fact, by using this management framework, recreation quality and quantity, and visitor satisfaction were ensured. Also, visitors can obtain a good experience from their recreation and activities in a park. Critical indicators are related to recreation and their variation should be considered by managers. When the standard level of critical indicators was determined, managers should control them. If critical indicators are not in the range of standard level, visitor satisfaction and experience will be affected. Thus, recreation which is the most important goal of urban park will be disturbed.