The present invention refers to a separator and an electrochemical device having the same. The separator of the present invention comprises a non-woven fabric substrate obtained from fibers and having multiple pores formed between the fibers; and a polymer coating layer formed on a part or the whole of the surface of the fibers, wherein the polymer coating layer comprises a polymer having a tensile strength of 80 MPa or more, a tensile modulus of 3,000 MPa or more and a flexural modulus of 3,000 MPa or more.The separator of the present invention can reduce costs for manufacturing electrochemical devices, and it can control the size of pores present in the non-woven fabric substrate to prevent the generation of a leak current and provide improved mechanical strength.