Jet penetration depth (JPD) and bubble coalescence behavior were studied for two semi-circular nozzles (42 mm in I.D.) in a 500 mm I.D. semi-circular fluidized bed. The results showed that JPD of a nozzle didn＇t change as nozzle distance varies for the configuration of double nozzles, which was consistent with the previous result in a two-dimensional fluidized bed [6]. Based on data from this study and literature, an empirical correlation was given for prediction of JPD in gas-solids fluidized beds. Furthermore, two types of gas coalescence, jet coalescence and bubble coalescence, were found and characterized in the research on disturbance of double nozzles＇ flow. And the criterion for these two types of coalescence, as well as the relationship between height of gas coalescence and operating conditions, were finally discussed.