$a_1,a_2,...,a_{100}$ are permutation of $1,2,...,100$. $S_1=a_1, S_2=a_1+a_2,...,S_{100}=a_1+a_2+...+a_{100}$Find the maximum number of perfect squares from $S_i$
1. We are given a permutation \(a_1, a_2, \ldots, a_{100}\) of the numbers \(1, 2, \ldots, 100\). We define the partial sums \(S_i = a_1 + a_2 + \cdots + a_i\) for \(i = 1, 2, \ldots, 100\).
2. We need to find the maximum number of perfect squares among the \(S_i\).

3. First, note that the sum of the first 100 natural numbers is:
   \[
   \sum_{i=1}^{100} i = \frac{100 \cdot 101}{2} = 5050
   \]
   Since \(5050 < 72^2 = 5184\), the largest possible perfect square \(S_i\) can be is \(71^2 = 5041\). Thus, \(m_k \leq 71\).

4. Let \(P_k = m_k^2\) be the \(k\)-th perfect square. We add \(P_0 = 0\) to the sequence for convenience.

5. The difference between consecutive perfect squares is:
   \[
   P_{k+1} - P_k = (m_k + 1)^2 - m_k^2 = 2m_k + 1
   \]
   This difference is always an odd number.

6. Since there are at most 50 odd numbers between 1 and 100, we get a contradiction if \(m_k \geq 61\). This is because:
   \[
   m_{61} = (m_{61} - m_{60}) + (m_{60} - m_{59}) + \cdots + (m_2 - m_1) + (m_1 - m_0) \geq 50 \cdot 1 + 2 \cdot 11 = 72
   \]
   This implies that the maximum number of perfect squares is 60.

7. To construct the sequence, we start with:
   \[
   P_1 = 1^2, \quad P_2 = P_1 + 3 = 4, \quad \ldots, \quad P_{49} = P_{48} + 97 = 49^2, \quad P_{50} = P_{49} + 99 = 50^2
   \]

8. For \(P_{51}, P_{52}, \ldots, P_{60}\), we use the formula \((p+1)^2 = p^2 + 2p + 1\):
   \[
   \begin{aligned}
   &50^2 + 82 + 62 + 42 + 18 = 52^2 = P_{51}, \\
   &52^2 + 84 + 64 + 44 + 20 = 54^2 = P_{52}, \\
   &54^2 + 86 + 66 + 46 + 22 = 56^2 = P_{53}, \\
   &56^2 + 88 + 68 + 48 + 24 = 58^2 = P_{54}, \\
   &58^2 + 90 + 70 + 50 + 26 = 60^2 = P_{55}, \\
   &60^2 + 92 + 72 + 52 + 28 = 62^2 = P_{56}, \\
   &62^2 + 94 + 74 + 54 + 30 = 64^2 = P_{57}, \\
   &64^2 + 96 + 76 + 56 + 32 = 66^2 = P_{58}, \\
   &66^2 + 98 + 78 + 58 + 34 = 68^2 = P_{59}, \\
   &68^2 + 100 + 80 + 60 + 36 = 70^2 = P_{60}.
   \end{aligned}
   \]

Conclusion:
The maximum number of perfect squares among the sums \(S_i\) is 60.

The final answer is \(\boxed{60}\).