Output growth at China's factories and workshops for the first two months slowed to 5.3 percent on-year, from 5.7 percent in December, a multi-year low and short of forecasts.
Growth had been expected to cool to 5.5 percent from December's 5.7 percent. Most analysts believe activity may not convincingly stabilize until the middle of the year.
Weekly utilization rates at steel mills across China fell to 62.98 percent last week as of March 8, the lowest level in a year, data compiled by Mysteel consultancy showed.
In January and February auto sales continued to fall and manufacturing activity sunk.
China is grappling with a decline in global demand - most notably from the United States, which launched a trade war past year.
Private-sector fixed-asset investment, which accounts for about 60 percent of overall investment in China, rose 7.5 percent in the same period, compared with an 8.7 percent rise in 2018, data from the National Bureau of Statistics showed.
That marks the strongest growth for the January-February period since 2014, when it rose 19.3 percent.
Job shedding by export-oriented companies led to a jump in the unemployment rate last month, said Li Xiru, an official with the statistics bureau.
Falling property sales in Jan-Feb due to Lunar New Year factors.
China's fixed asset investment (or FAI) rose by 6.1%, which was in line with economists' expectations.
However, retail sales remain near a 15-year low, said Julian Evans-Pritchard of Capital Economics in a note, adding that "the near-term outlook still looks downbeat".
President Donald Trump said on Wednesday he was in no rush to complete a trade pact with China and insisted that any deal include protection for intellectual property, a major sticking point between the two sides during months of negotiations.
China's survey-based jobless rate rose to 5.3 percent in February, from 4.9 percent in December, though it was below the government's target of 5.5 percent this year.
Thursday's data showed sales of appliances and furniture softened considerably early in the year, possibly linked to worries about the cooling property market and a 3.6 percent drop in home sales.
Regulators have ordered big banks to increase loans to smaller firms by more than 30 percent this year, despite the risk of more bad loans. Infrastructure spending ticked up 4.3% in January and February, from 3.8% the same time a year ago.