It is unclear whether all 9.4 million Qingdao residents would be tested as authorities did not give a precise figure.
China has extensive, quick test capabilities and by noon Monday the health commission said more than 277,000 people had already been tested in Qingdao, with nine positive results.
In June large areas of the capital Beijing were subject to mass tests after the city of more than 20 million detected virus cases linked to a food market.
China has bounced back since the virus emerged, closing the country down and hammering the world's second-largest economy.
Hundreds of millions traveled across the country for the "Golden Week" holiday last week as the country edges back to growth, while rapid tests and swift lockdowns have tamped down secondary waves of the virus.
The picture elsewhere in the world, however, is strikingly different as countries battle new waves and alarming spikes.
Britain's leader Boris Johnson will unveil his tiered system on Monday, with northwestern Liverpool expected to be the only city placed in the top category.
Like governments across Europe, Johnson's Conservative cabinet is seeking to balance bringing down the rate of new infections against frustration and concern about the economy.