Open government data portal (OGDP) makes the government transparent and enables the public to obtain massive data. However, the public know little about OGDP and the value of government data is still waiting for exploration. This paper takes IS success model, TAM and the paradigm of SOR to study the factors affecting users’ response to OGDP. It selects system quality, data quality, interactivity, policy environment, perceived usefulness, perceived ease of use and use intention as variables to build research model. After collecting 93 valid respondents, we utilized SmartPLS to conduct statistical analysis for the model. The exploratory study finds that data quality affects system quality, and system quality positively affects perceived usefulness and perceived ease of use. Policy environment affects users’ interactivity with OGDP, then influences their perception of the system, ultimately responds as use intention. Finally, this paper confirms that the mediating effect only exsists in interactivity and perceived ease of use on the relationship between policy environment and use intention. Then it proposes suggestions for improving data and system quality, enhancing interactivity to encourage the public to use OGDP more frequently, and create value with government data.