Tā shì wǒ duōnián de gōngzuò huǒbàn, fēicháng kàopǔ.
He's been my work partner for years and is very reliable.
Tips
usage
工作伙伴 is warmer than 同事 (coworker) - it implies real collaboration and shared work, closer to English 'work partner' or 'teammate'. 合作伙伴 (cooperation partner) is the more formal, business-deal version.
