To study the effect of heavy metal stress on bacterial antibiotic resistance, a Gram-negative bacteria isolated from swine wastewater in Guangzhou was characterized and identified as Pseudomonas alcaligenes LH7. The minimal inhibition concentration (MIC) of heavy metals (Cu²⁺, Zn²⁺ and Cr⁶⁺) and antibiotic susceptibility test were determined by the methods of Kirby-Bauer disk diffusion and agar dilution. Furthermore, with the joint effect of type and concentration of heavy metals, the inhibition zone diameter of the tested antibiotics (erythromycin, amoxicillin, cephradine and tetracycline) was measured by vernier caliper. The results showed that the MICs of Cu²⁺, Zn²⁺ and Cr⁶⁺ were 125 mg/L,125 mg/L and 100 mg/L, respectively. Multiple antibiotic resistance was also observed. The Pseudomonas alcaligenes LH7 showed resistance to erythromycin, amoxicillin, cephradine and tetracycline. The interaction of antibiotics and heavy metals significantly affected bacterial resistance (P﹤0.05). There were three kinds of cross-effects between antibiotics and heavy metals according to the types and concentrations of heavy metals. Firstly, the effect of heavy metals on antibiotic resistance could be co-resistance at low concentrations but synergic germicidal at high concentrations, such as Cr⁶⁺ and erythromycin, Zn²⁺ and erythromycin, Cu²⁺ and cephradine. Secondly, the effect of heavy metals on antibiotic resistance could be synergic germicidal at low concentrations but co-resistance at high concentrations, such as Cr⁶⁺ and amoxicillin, Zn²⁺ and amoxicillin. Finally, the antibiotic resistance was only associated with the types of heavy metal, such as Cu²⁺ and tetracycline or amoxicillin or erythromycin, Cr⁶⁺ and cephradine. Co-existence of heavy metals in environment will change the ecological harm and environmental behavior of antibiotics, and affect the development and application of relative pollution prevention techniques, so this is a field worthy of attention.