Mixed forestry with bamboo (Phyllostachys heterocycla cv. pubescens) and Chinese fir (Cunninghamia lanceolata) has expanded; however, the relationship between the species is both positive and negative. In the present study, the influence of the extract of several organs (including fresh leaves, dry leaves, branches, stems, rhizomes, and roots), litter, and rhizosphere soil of P. heterocycla cv. pubescens on C. lanceolata seed germination, as well as the allelopathy between the two species were analyzed. The results showed that (1) the extract from the organs of P. heterocycla cv. pubescens inhibited C. lanceolata seed germination during the early stage of the process. Further, when the extract solution concentrations were high at 1:25 and 1:50, C. lanceolata seed germination inhibition was higher than that at the lower concentrations. (2) Low concentrations of the extract promoted C. lanceolata seed germination, whereas high concentrations inhibited it during the late stage of the process and the effect appeared more slowly. (3) The litter extract inhibited C. lanceolata seed germination, except when the concentration was 1:50, the germination rate was slightly higher than that of the control. However, the extract liquid of rhizosphere soil generally promoted C. lanceolata seed germination; especially low concentrations, significantly enhanced germination. Therefore, the extract liquid of P. heterocycla cv. pubescens rhizosphere soil could be used to promote C. lanceolata seed germination in mixed forest management, and this study provided a reference for the mixed forest management and production of these two species.