Thek-ε turbulent model is used to obtain a mathematical model of a vertieal round buoyant jet in static, linearly stratified environment. The Hybrid Finite Analytic Method and a staggered grid are used to calculate the whole field of this flow pattern. The centerline velocity and temperature, the maximum height of rise, the height of neutral buoyancy, the demarcation between buoyant jet and mushroom-cloud regions, and the demarcation between mushroom-cloud and spreading layer regions are calculated.