Abstract: With application of multielement recurrence and correlation analysis,its aim was to reveal the effect and changeable regularity among fresh alfalfa yield,branches and the strain height in half-drought area. The result showed that fresh alfalfa yield was correlated to the branches,if fresh alfalfa yield of 1 hm2 reaches 84 tons,the condition,above 5.8 million brances and no less than 70 cm in height,should be needed,if fresh alfalfa yield of 1 hm2 is 70 tons on averge,the branches is negatively correlated to its height,but it isn′t marked,thus it exists the risk by increasing branches and the height to abtain the yield. It should control branches and its height in administration measure in time to keep them in the reasonable range.