Objective To compare the safety and efficacy of simultaneous bilateral biliary metal stents with plastic stents under endoscope for treatment of malignant hilar biliary obstruction (MHBO). Methods From May 2007 to December 2011, 142 MHBO patients were selected for this study, with 32 receiving bilateral metal stent drainage and 110 receiving bilateral plastic stent drainage. The success rate of endoscopic operations, postoperative jaundice-reducing effect, post-endoscopic retrograde cholangiopancreatography (ERCP) complications, and stent patency period were observed. Results The procedures were successful in all patients in the two groups. The postoperative jaundice-reducing effect rates were 96.9%(31/32) in the metal stent group and 88.2%(97/110) in the plastic stent group (P>0.05). Two patients in the metal stent group and six in the plastic stent group had post-ERCP cholangitis, which was relieved by anti-inflammatory intervention, replacement of stents or endoscopic nasobiliary drainage. Two patients in the plastic stent group had stent slip. There were no pancreatitis, gastrointestinal bleeding, perforation or ERCP-related deaths in the two groups. Two patients in the metal stent group and 4 in the plastic stent group died, and the biliary stents were patent until they died. Eight patients in metal stent group and 29 patients in the plastic stent group developed recurrent obstructive jaundice, which were treated by reimplantation or replacement of the plastic stents. The post-ERCP complication rates were similar in the two groups (P>0.05). The median patency period of the metal stent was (248.53±138.61) d and that of the plastic stent was (101.76±38.53) d, showing significant difference by Log-rank test (P<0.001). Conclusion For Bismuth Ⅱ-type, bilateral bile duct invaded, or non-resectable MHBO patients, if biliary drainage range permits and the expected survival period >3 months, double metal stent biliary drainage has more advantages.