Objective To evaluate the efficacy of 0.3％ sodium hyaluronate ophthalmic solution in mild-to-moderate dry eye patients.Metbods A prospective,multicenter,and self-controlled clinical trial was performed on 200 patients who were diagnosed as mild-to-moderate dry eye from January 2015 to June 2017 in Eye Institute of Xiamen University,Eye & ENT Hospital of Fudan University,Zhongshan Ophthalmic Center,Xiangya Hospital Central South University,Eye Hospital of Wenzhou Medical University,and Beijing Tongren Hospital,Capital Medical University.The study protocol was approved by the Ethics Committees of Eye Institute of Xiamen University,written informed consent was obtained from each patient prior to any medical examination.All patients were treated with 0.3％ sodium hyaluronate ophthalmic solution 6 times per day (one drop each time) for 28 days.Corneal fluorescein sodium staining,tear film break-up time (BUT),Schirmer Ⅰ test (S Ⅰ t),degree of conjunctival hyperemia,eyelid margin,meibomian gland secretion,secretory capacity of meibomian gland and subjective symptoms were assessed at baseline,on the 14th day and 28th day after treatment.Bulbar impression cytology was evaluated at baseline and on the 28th day after treatment.Irritation of 0.3％ sodium hyaluronate ophthalmic solution was estimated on the 14th day and 28th day after treatment.Results The total score of subjective symptoms,BUT,S Ⅰ t,degree of conjunctival hyperemia were significantly different among different treatment time points (F =108.969,27.598,16.838,36.750;all at P＜0.01).Compared with before treatment,the total score of subjective symptoms was significantly decreased,the degree of conjunctival hyperemia and the total corneal fluorescein sodium staining point number were significant decreased on the 14th day and 28th day after treatment.The total score of subjective symptoms,degree of conjunctival hyperemia and total corneal fluorescein sodium staining point number on the 28th day after treatment were significant lower than those on the 14th day after treatment.Compared with before treatment,the BUT was significantly longer and the S Ⅰ t scores were significantly increased on the 14th day and 28th day after treatment.The BUT on the 28th day after treatment was significantly longer than that on the 14th day after treatment;no significant difference in S Ⅰ t was observed between the 28th day and the 14th day after treatment.The scores of palpebral margin change,meibomian gland secretory ability and secretion characteristics were not significantly different among different treatment time points(H=0.255,2.356,0.294;all at P＞0.05).The impression cytology grade on the 28th day after treatment was 1.08±0.74,which was significantly lower than 1.53±0.76 before treatment (t =5.979,P＜0.01).The number of goblet cells on the 28th day after treatment was significantly higher than that before treatment (U =1 806.500,P＜ 0.01).On the 14th day after treatment,70％ of the patients indicated that the drug was non-irritating,and no patient had intolerable irritation affecting daily lives.All patients had good tolerance to this drug.Conclusions The use of 0.3％ sodium hyaluronate eye drops can improve the symptoms and signs of mild to moderate dry eye,which can be widely used for mild-to-moderate dry eye patients in clinic.