A reverse-phase HPLC method to determine DL-Carnitine Hydrochloride in pharmaceutical preparation is described. UV absorption derivatives of DL-Carnitine Hydrochloride were formed with p-Bromophenacyl Bromide in an essentially quantitative manner using crown ether as catalyst. The DL-Carnitine-bromophenacyl ester absorbed UV radiation strongly at 254nm, allowing the detection of as small a quantity as 12.5ng of DL-Carnitine Hydrochloride. A linear defection range was $5;{ imes};10-8 ;{sim};5;{ imes};10-7M$ of DL-Carnitine Hydrochloride. And the linear regression at various drug concentration was =0.999 (n=10). The DL-Carnitine Hydrochloride in pharmaceutical preparation was successfully derivatized and separated from other constituents by reverse phase HPLC with detection at 254 nm.