This study is to investigate the tumor invasion and metastasis inhibition effects of the immunoconjugate composed of lidamycin and anti-type IV collagenase monoclonal antibody Fab' fragment.  Boyden chamber assay was used to evaluate the influence of Fab'-LDM on HT-1080 cells invasion ability, gelatinase spectrum was used to measure the change of invasion factor MMP-2 and MMP-9’s secretion, and RT-PCR was adopted to determine TIMP-1 mRNA expression level.  The immunoconjugate inhibition of tumor in situ metastasis was also tested in nude mice.  The Fab'-LDM conjugates had dose-dependent inhibition effect on HT-1080 cells’ invasion.  At the concentrations of 5 and 10 nmol·L⁻¹, the Fab'-LDM inhibited the invasion by (60 ± 12) % and (79 ± 11) % respectively.  At the concentration of 5 and 10 nmol·L⁻¹, the Fab'-LDM inhibited the secretion of MMP-2 by (42 ± 8) % and (54 ± 6) % and that of MMP-9 by (57 ± 3) % and (87 ± 1) %, respectively.  RT-PCR indicated that conjugates increased the anti-invasion factor TIMP-1 level.  The in vivo experiment showed   that, compared with the control group, the tumor inhibition rate in Fab', Fab'-LDM, and LDM group equaled to (30 ± 13) %, (86 ± 26) %, (74 ± 22) % respectively.  In conclusion, Fab'-LDM could inhibit the invasion and metastasis of tumor and it might be a new tumor biotherapy agent.