A new diterpenoid, acetyl danshenxinkun A (1), and five known tanshinones, tanshinone ⅡA (2), 1,2-dihydrotanshinone Ⅰ (3), tanshinone Ⅰ (4), cryptotanshinone (5), and 15,16-dihydrotanshinone Ⅰ (6) were isolated from the roots of Salvia miltiorrhiza. Their structures were determined by spectroscopic methods.