Porcine astroviruses (PAstVs), are widely distributed viruses that are highly prevalent in swine herds. In this study, a novel type 4 porcine astrovirus strain (designated as PAstV4/Tianjin/2018) was identified in a fecal sample from a diarrheal piglet in Tianjin, China and its complete genomic sequence was determined by RT-PCR. Sequence analysis showed that this strain had a capsid protein with a highly variable C-terminal domain, a typical ribosomal frameshifting signal, and a conserved subgenomic promoter sequence. Recombination analysis indicated that PAstV4/Tianjin/2018 was a novel recombinant strain, and a recombination breakpoint was identified at nt position 4220 of the genome. The novel recombinant porcine astrovirus identified in China will be useful for understanding the origin, genetic diversity, and evolution of enteric viruses.