An AE measurement system that uses a laser interferometer has been developed to evaluate microfractures at elevated temperatures in various materials. This technique has the advantage that it can estimate the temperature where microfractures were generated. The results give useful information to control process conditions. AE during sintering ceramics and thermal spying of ceramic powder on metal substrates were successfully detected by this laser AE measurement system. Effect of process conditions on damage process was discussed from the detected AE behaviour during in-process monitoring.