An experiment was conducted to examine the near-field behavior of negatively bu oyant planar jets in flowing environment. Hot water jet was projected d ownwards at different angles from a slot into a uniform cross flow. Micro Acoust ic Doppler Velocimeter (Micro ADV) system is used to measure the velocity and tu rbulent fluxes of Reynolds stresses. The whole field temperatures were measured with fast response thermocouples. Pure jets experiments were made also to study the effect of buoyancy in negatively buoyant jets. It is found that the influenc ed area of hot jets is larger than which of pure jets when the jet angle is 90° and the influenced area of hot jets is smaller than which of pure jets when the jet angle is 45°. The difference is not obvious at 60° angle jets. This means that the rising of temperature has effect not only on negatively buoyancy, but also on the intensity of turbulence. The contrast of these two influences domina tes the trend of jet flow. An experiment was conducted to examine the near-field behavior of negatively buoyant planar jets in flowing environment. Hot water jet was projected d ownwards at different angles from a slot into a uniform cross flow. Micro Acoust ic Doppler Velocimeter (Micro ADV) system is used to measure the velocity and tu rbulent fluxes of Reynolds stresses. The whole field temperatures were measured with fast response thermocouples. Pure jets experiments were made to to study the effect of buoyancy in negatively buoyant jets. It is found that the influenc ed area of hot jets is larger than which of pure jets when the jet angle is 90 ° and the influenced area of ​​hot jets is smaller than that of pure jets when the jet angle is 45 °. The difference is not obvious at 60 ° angle jets. This means that the rising of temperature has effect not only on negatively buoyancy, but also on the intensity of turbulence. The contrast of these two influences domina tes the trend of jet flow.