In steam pipelines of nuclear power plants, thermal power plants, or other industrial settings, direct contact between steam and condensate water may occur under unexpected operating conditions. The contact of steam with cold water within the pipeline can easily lead to bubble collapse and subsequently trigger the water hammer phenomenon, which is referred to as condensation-induced water hammer (CIWH). The occurrence of CIWH can generate substantial pressure fluctuations in a short period, causing severe hazards to the pipeline equipment and personnel safety in power plants. This paper established a mechanism experimental platform based on the possible CIWH phenomenon in nuclear power plant steam pipelines and conducted mechanistic experimental research on factors such as steam pressure and temperature of condensate water at the bottom of the experimental Section that have significant influences on the water hammer phenomenon. According to the characteristics of the water hammer phenomenon as it varies with the influencing factors, measures to suppress the occurrence of water hammer in power plants and mitigate its detrimental effects were derived. The experimental results indicate that the influence of the condensate water temperature factor on water hammer presents a monotonic variation characteristic. The lower the temperature of the condensate water is, the more obvious the pressure fluctuation caused by water hammer becomes. The influence of the pressure factor usually interacts with other factors and there is no obvious monotonic variation law. Reasonable control of pressure and temperature within a certain range can effectively mitigate the pressure fluctuation of water hammer.