When a patient is positioned at insulated bed and practitioner is positioned at insulated floor, that condition could be a cause of lessening effect in acupuncture practice. We investigated how Ground connection and Insulation could influence on the electrical meridian potential between practitioner and patient during acupuncture practice. We treated 30 normal healthy subjects with acupuncture and measured changes in the electrical potential between the stomach meridian points ST-39 and ST-37 in response to light touch after insertion of a needle at ST-36. At first, we stimulated non-insulated needle and measured electrical potentials for non ground, patient ground only, practitioner ground only, all ground respectively. Then we used insulated needles and measured same as above. Non-insulated all ground subject elicited positive mean potential $44.6{pm}19.2{mu}V$ and showed $181.4{pm}59.7{mu}V$ peak to peak potential. Practitioner ground only showed negative mean potential of $51.5{pm}9.3{mu}V$ and $367.4{pm}27.8{mu}V$ of peak to peak potential. Patient ground only revealed no mean potential of $2.9{pm}1.3{mu}V$, $16.4{pm}11.9{mu}V$ of peak to peak potential. All ground showed no mean potential of $1.6{pm}0.7{mu}V$, $3.3{pm}1.9{mu}V$ of peak to peak potential. In case of Insulated condition, there elicited no mean potential. Non ground and Practitioner only showed weak value of peak to peak potential as $7.8{pm}2.6{mu}V$ and $8.4{pm}2.5{mu}V$ each. But patient only and all ground showed no potential as $4.7{pm}2.2{mu}V$, $3.4{pm}2.2{mu}V$, respectively. Therefore, Ground connection modulate the energy transfer course between practitioner and patient. Insulation block energy transfer but static electrical impulse between practitioner and patient.