Hyperthermia　treatments　of　tumours　are　attracting　more　and　more　attention　from　physical　doctors　and　researchers.　In　particular,　invasive　microwave　coagulation　(IMC)　therapy　is　a　newly　developed　and　effective　method　for　the　treatment　of　liver　tumours.　Generally　successful　applications　of　IMC　are　based　on　accurate　temperature　measurements　of　the　tissues　as　the　microwaves　take　effect.　As　a　noninvasive　technology,　ultrasonic　thermometry　is　based　on　the　correlation　between　temperature　and　ultrasound　speed　or　ultrasound　decay　coefficients　of　tissues.　This　paper　presents　the　design　of　a　double　ultrasonic　pulse　transmission/receiving　circuit　used　in　ultrasonic　thermometry.　The　circuit　can　synchronously　produce　the　double　ultrasonic　pulse　required　by　ultrasonic　thermometry　and　can　successfully　receive　weak　ultrasonic　echo　signals.　Some　key　wave-shapes　used　in　experiments　are　presented.　The　experimental　results　indicate　that　the　circuit　is　reliable　and　has　good　functionality.　©　2006　Taylor　&　Francis.