Sixty-four per cent of Pakistanis have a favourable opinion of Sharif, essentially unchanged from the 66 per cent who expressed this view in a survey conducted weeks before his election victory last year, the Pew Research said.
However, as a result of the weeks of protest by Khan in Islamabad which is being attended by thousands of people, the mood of the people of Pakistan is not that great.
Protesters have been camping for more than a week to force Sharif's resignation.
Popularity rating of the powerful Army has also increased as a result of the months of chaos, the Pew Research said as it released details of its latest survey.
About a third (32 per cent) give him an unfavourable rating, Pew said.
Khan also receives more positive (53 per cent) than negative (24 per cent) reviews, although his ratings have slipped by 17 percentage points over the past two years, the Pew said.
Meanwhile, the country's military, always a key player in Pakistan's politics, receives stunningly high ratings.
Fully 87 per cent say the military is having a good influence on the nation, up from an already high 79 per cent in 2013, it added.
While most Pakistanis remain unhappy with the country's direction, the public mood is more positive than it has been in recent years.
While only 25 per cent are satisfied with the way things are going in Pakistan, this is a significant improvement from the eight who felt that way in 2013.
The percentage saying the economy is in good shape has more than doubled since last year, rising from 17 per cent to 37 per cent.
And 36 per cent now expect the economy to improve in the next 12 months, Pew reported.
Moreover, while Pakistanis still believe their country faces a long list of challenges, they are now less likely to describe as very big problems issues such as public debt, the situation in Afghanistan, tensions between Sunni and Shia Muslims, and corruption.
When asked to rate the greatest threat facing their country, the Taliban, al Qaeda or India, Pakistanis tend to cite their neighbour to the east: 51 percent believe India is the biggest threat, up from 38 percent in 2013.
One-in-four name the Taliban and only two percent say al Qaeda, Pew said.
"Roughly seven-in-ten (71 per cent) express an unfavourable view of India, while only 13 percent give it a positive rating," the polling agency said, adding that only 14 percent give the US a favourable rating, and just seven have confidence in President Barack Obama.
Still, the percentage of Pakistanis voicing a negative view of the US and President Barack Obama has declined slightly over the last few years.