The purpose of this study was to investigate responses of pear cultivars ‘Niitaka’ and ‘Chuwhangbae’ under short period heating on cold resistance level of flower buds. Experiment was conducted using annual shoots flower bud which were artificially heated (AH) during 72 hour at room condition (18–20°C). To assay for cold resistance, the cultivars were treated and observed under negative temperatures −10, −15, −20 and −25°C during the winter period in 2012 and 2013. Our findings revealed that ‘Chuwhangbae’ which was treated under control and artificial heating treatments was more resistant to low temperature than ‘Niitaka’ showing decreasing level of flower buds damages by mid-January although in early March an increasing level of damages was observed again. Cold resistant cultivar ‘Chuwhangbae’ responded more sensitively to external environments. This means that ‘Chuwhangbae’ restructures the plant protoplasts and process the transition to the new metabolic energy level in an efficient manner when triggered by effective negative temperatures thereby resulting in hardening process. We assume that this might be closely related with dormancy period, concentration of the mineral elements, water potential and transition processes of metabolism to the new energetic level. With a rise in temperature, cold tolerance in pear cultivars significantly decreased and this is related to intensive development of the floral organs. The chilling requirements for blossoming of ‘Niitaka’ was higher than ‘Chuwhangbae’.