To investigate the recent prevalence and molecular epidemiological characteristics of por-cine diarrhea viruses in Sichuan Province,this study used fluorescence quantitative PCR to detect porcine diarrhea samples from multiple regions in Sichuan Province from 2021 to 2023.RT-PCR was used to identify the genotypes of PEDV,PoRVA,PDCoV,and PTV,and their genetic variabil-ity,evolutionary characteristics,and recombination events were analyzed.The results showed that PEDV,PoRVA,PDCoV,and PTV were still prevalent in Sichuan region,with overall positive rates of 14.2％(40/281),13.2％(37/281),15.6％(44/281),and 12.5％(35/281),respectively.PEDV mixed infection with other pathogens was the most common.This study obtained a total of six strains of G2b PEDV,three strains of G3 PDCoV,three strains of G9P[13]PoRVA,one strain of G3P[13]PoRVA,three strains of Type 5 PTV,and one strain of Type 9 PTV.Compared to the seven vaccine strains including CV777,DR13,KPEDV-9,Chinju99,KNU-0801,AJ1102,and LW/L,the 6 PEDV strains showed multiple amino acid mutation sites in the COE region and S1D epitope region.Among them,the strains PSCLZ01 and PSCMY04 formed a separate branch in the phylogenetic tree.The three PDCoV strains have a closer genetic evolution distance to the previ-ously prevalent strains in Sichuan,but they also have 6-48 amino acid mutations compared to them.The four PoRVA strains have 104-108 amino acid variations in the VP4 gene compared to the early vaccine strain LLR,and they have 25 common amino acid variations in the VP7 gene.From the phylogenetic tree,the VP7 gene of RSCMY01/G3P[13]belongs to the same branch as the Heilongjiang strain LNCY,but its VP4 gene clusters with the Sichuan strain SCYA-C7,indica-ting that this PoRVA strain may have undergone genetic reassortment during inter-provincial transmission between different genotypes.It is worth noting that in the detected samples of PTV-5 and PTV-9,other diarrheal viruses tested negative,indicating that these two genotypes of PTV may be important pathogens causing porcine diarrhea.Additionally,the S gene of PEDV PSCLZ01 strain and PDCoV PCSCMY02 strain have undergone recombination events,and their parental strains come from different regions,both domestic and international.These findings reveal the main types of porcine diarrheal viruses,as well as their genetic diversity and variations in Sichuan Province in recent years.This study enriches the molecular epidemiological data of porcine diarrhe-al pathogens in the region and provides an important theoretical basis for the prevention,control,and purification of porcine diarrhea in the local area.