The work aims to prepare mulch films with poly (terephthalate-adipate-butanediol) (PBAT) and poly (3-hydroxybutyrate)-co-4-hydroxybutyrate (P34HB) and study their effect on tomato growth, so as to promote plant growth and reduce crop yield caused by film residue. The technical route was to blend PBAT and P34HB at 9∶1, 8∶2 and 7∶3 mass ratios, and produce three mulch films with different mechanical and barrier properties through water-cooled granulation and blow molding, and then apply them to tomato production. The results showed that with the increase of P34HB content, the tensile strength and moisture permeability of the composite film were enhanced. The 9∶1 film had a certain effect on tomato production, and the residual amount of a single row was about 16 pieces. It is concluded that the performance of the PBAT/P34HB (9∶1) film can satisfy the tomato production. It has the effect of increasing production, and reduces the pollution caused by the film residue.