Muscovite mica, a natural layered material with excellent flexibility and super flat surface, which can be well integrated into flexible optoelectronic devices. In addition to its ability to withstand higher temperatures than conventional flexible substrates, its natural high surface energy and hydrophilicity give muscovite mica a good adsorption capacity for two-dimensional materials. Here, we combined mica substrate with a thin film of MoS2 nanosheets floating on the water surface to produce a flexible, heat-resistant photodetector. The device exhibits excellent response stability, superior flexibility and fast response time (976 ms of rise time and 161 ms of decay time). Moreover, the responsivity of 8.45 μA∙W-1 and the detectivity of 4.1 × 107 Jones are realized respectively. After 500 bending cycles, the photodetector still possesses the ability to output the photocurrent signal continuously and stably. What's more, the devices have a consistent performance after 300 °C bake, showing excellent stability and fast response. This work shows great potential for flexible photodetectors and contributed to the development of flexible optoelectronic devices from the room-temperature to heat-resistance practical applications.