The invention discloses a cyclone separator in the field of medicinal equipment. The cyclone separator includes a circular cylindrical body, an inverted-conical cylindrical body, an air inlet pipe, an air outlet pipe and a material discharge pipe. The top of the circular cylindrical body is sealed by a top cover. The bottom of the circular cylindrical body is connected to the top of the inverted-conical cylindrical body. The bottom of the inverted-conical cylindrical body is connected to the material discharge pipe. The air inlet pipe is horizontally tangented with the circular cylindrical body. The air outlet pipe penetrates the top cover and is stretched into the circular cylindrical body. A rotary joint sleeves the bottom of the inverted-conical cylindrical body and is provided with a lower air inlet pipe, of which an air inlet direction is opposite to the air inlet direction of the air inlet pipe. A filtering membrane is arranged in the air outlet pipe. The cyclone separator can ensure a powder being less than specified size to be completely separated while the powder being not less than the specified size to be remained in the cyclone separator, thereby ensuring quality of products and meanwhile reducing loss of the powder.