A multi-tube air-lift loop reactor (MT-ALR) is presented in this paper.Based on the energy conserva-tion,a mathematical model describing the liquid circulation flow rate was developed,which was determined by gasvelocity,the cross areas of riser and downcomer,gas hold-up and the local frictional loss coefficient.The experimen-tal data indicate that either increase of gas flow rate or reduction of the downcomer diameter contributes to higherliquid circulation rate.The correlation between total and thelocal frictional 1oss coefficients was also established.Effects of gas flowrate in two risers and diameter of downcomer on the liquid circulation rate were examined.Thevalue of total frictional loss coefficient was measured as a function of the cross area of downcomer and independentof the gas flow rate.The calculated results of liquid circulation rates agreed well with the experimental data withan average relative error of 9.6%. A multi-tube air-lift loop reactor (MT-ALR) is presented in this paper. Based on the energy conserva- tion, a mathematical model describing the liquid circulation flow rate was developed, which was determined by gasvelocity, the cross areas of riser and downcomer, gas hold-up and the local frictional loss coefficient. the experimen-tal data indicate that either increase or gas flow rate or reduction of the downcomer diameter contributes to higher liquid circulation rate. The correlation between total and the local frictional 1oss coefficients was also established. Effects of gas flowrate in two risers and diameter of downcomer on the liquid circulation rate were investigated. The value of total frictional loss coefficient was measured as a function of the cross area of ​​downcomer and independent of the gas flow rate. The calculated results of liquid circulation rates agreed well with the experimental data withan average relative error of 9.6%.