Printed circuit heat exchanger (PCHE) is the core component of LNG floating storage and regasification unit (FSRU) at offshore conditions. The flow distribution among the small mini-channels becomes more complex and changeable, and it is prone to rapid deterioration under sloshing conditions. This seriously affects seriously affects the regasification efficiency and operational safety of FSRU. In this regard, a three-dimensional mathematical model suitable for analyzing flow and heat transfer of supercritical LNG in PCHE under sloshing conditions is constructed, introducing the additional periodic inertial force caused by sloshing and calculation correlation of LNG multi-component physical properties through UDF. Then the related numerical research is carried out and the following conclusions are obtained. The flow rate and temperature of supercritical LNG in each channel of PCHE periodically oscillate, and the uniformity of the working fluid distribution is obviously deteriorated when inducing the sloshing condition. The relative standard deviations of the flow rate and temperature distribution among channels during the sloshing process are significantly higher than that at the initial steady value, and the max value even reaches more than 3 times the initial steady state value. The larger the sloshing amplitude and the sloshing frequency, the more uneven the flow distribution and temperature distribution among channels of PCHE. When the sloshing is applied in the flow direction of the channel, the deterioration of the flow distribution caused by the sloshing effect is obviously weaker, and the oscillation amplitude of the parameters in the channel is obviously reduced, compared to the situation when the sloshing is applied in the direction vertical to flow direction of the channel.