A micro-nano channel structure, a method for manufacturing the micro-nano channel structure, a sensor, a method for manufacturing the sensor, and a microfluidic device are provided. The micro-nano channel structure includes: a base substrate; a base layer, on the base substrate and including a plurality of protrusions; a channel wall layer, on a side of the plurality of the protrusions away from the base substrate, the channel wall layer has a micro-nano channel; a recessed portion is provided between adjacent protrusions of the plurality of the protrusions, an orthographic projection of the micro-nano channel on the base substrate is located within an orthographic projection of the recessed portion on the base substrate. The micro-nano channels have a high resolution or an ultra-high resolution, and have different sizes and shapes.