OBJECTIVE： To optimize the formulation of Mirabegron sustained-release tablets. METHODS： Using polyethylene oxide （PEO） and hydroxypropylmethyl cellulose （HPMC K4M） as the sustained release matrix， Mirabegron sustained-release tablets were prepared by powder direct compression technology. Using 1， 3， 5， 7 h accumulative release rate as indexes， the amounts of PEO， HPMC K4M and OPADRY® were optimized by composite design-response surface method， and then validated. Accumulative release rates of sustained-release tablet and original tablet （MyrbetriqTM） were compared in different pH mediums （water， pH 1.0 simulated gastric fluid， pH 4.5 acetate buffer solution， pH 6.8 phosphate buffer solution） at different rotation rates （100， 50    r/min）， and similiar factor f2 was calculated to fit drug release model of sustained-release tablet. RESULTS： In the optimized firmulation each Mirabegron sustained-release tablet contained mirabegron 25 mg， PEO 108.02 mg， HPMC K4M 21.69 mg， OPADRY® 2.27％. Relative error of accumulative release rates at 1， 3， 5， 7 h to predicted value were 4.78％， 3.48％， 0.69％ and －1.41％， respectively. f2 of release curves of sustained-release tablet and original tablet were higher than 65 in different pH medium at different rotation rates. The drug release of sustained-release tablet was fitted to zero-order release equation. CONCLUSIONS： Mirabegron sustained-release tablet by optimized technology is similar to original tablet in drug release behavior.