A rapid and real time detection system combing the laser spectroscopy with IWO-PSO-SVR is proposed for methane concentration. The detection system was designed based on near-infrared differential absorption and the best absorption wavelength at 1650nm and TDLAS and WMS. The power grows linearly from 5.0 to 10.6mW, the wavelength changed linearly from 1650~1651nm during the tuning process, the tuning rate increased from 0.0045 to 0.0115nm/mA. Gas samples were collected from a farm in Zibo, Shandong province in March 2019, 15samples date were randomly selected as the training set, the peak rare and methane concentration were used as the input and output values of the regression model, And the quantitative analysis model of algorithms of IWO-PSO-SVR、SVR、PSO-SVR and PSO-BP were established to predict the content of methane of test set. The experimental results showed that the IWO-PSO-SVR quantitative analysis model was effective:the Relative standard deviation of predicted and true values of four methane contents were 0.115%、0.109%、0.131% and 0.120%,less than 0.0014 respectively. The Determination coefficient were 0.9987、0.9966、0.9899 and 0.9975, high than 0.98 respectively. The elapsed time were 1.35, 1.54, 1.35 and 1.33s. After 1000 times of training, the detection accuracy of the model is 10^-5, compared with the same category detection system, it has high engineering application value.