Accurate identification of daughter minerals existed in fluid inclusions has a great significance for obtaining the geochemical information on fluids related to processes of sedimentation, diagenesis or mineralization, and using micro-Raman spectra to identify the types of daughter minerals is in-situ, nondestructive, high sensitive, good-stability, quick and convenient, so which has been widely used at present. In this paper, we used micro-Raman spectra, for the first time, to identify the types of daughter minerals in primary inclusions, which trapped in rock salt from the lower submember of Eocene Sha-4 member of Shahejie Formation (Es4x) in Dongying sag. On this basis, the indication significances of these daughter minerals to geochemical characteristics of paleo-brines in Eocene salt lake of Dongying sag were discussed in detail. The results show that anhydrite and starkeyite are the main daughter minerals in primary inclusions in rock salt of Es4x. Among them, anhydrite has strongest Raman band at 1 018 cm-1 and other five additional weaker bands at 500, 611, 629, 676, 1 131 cm-1, respectively. Starkeyite has strongest Raman band at 1 000 cm-1 and other three additional weaker bands at 462, 618, 1 156 cm-1. These two kinds of daughter minerals existed in primary inclusions indicate that salt lake brines contained small amount of compositions of CaSO4 and MgSO4, the brines just reached early stage of evapo-concentrated precipitations at this moment, that is, the end of sulfates deposit and the beginning of early stage of rock salt deposit, and halite was the main product of brines precipitation. Moreover, based on the precipitation temperature of anhydrite and starkeyite, the temperature of paleo-brines of Eocene salt lake during the early stage of evapo-concentrated precipitations was determined, namely, the values of temperature ranged from 37 to 61 ℃ and sedimentary environment was featured by drought.